1. Field of the Invention
The present invention relates to a conveyor device for conveying a belt-like material and, particularly, to a conveyor device capable of conveying a belt-like material by keeping stress applied to the belt-like material at a constant level even when the conveyance speed is changed.
2. Description of the Prior Art
In the prior art, when the conveyance speed on the transmitting side or receiving side is changed or intermittent delivery occurs for the convenience of a line at the time of conveying a belt-like material, a vertical loop type suspension conveyor as shown in FIG. 4 is used as conveyor means capable of adjusting the length of the conveyance path of the above belt-like material. Since the above belt-like material 1 is not supported between the transmitting conveyor 51 and the receiving conveyor 52, it is slackened and the amount of the slack is changed to adjust the length of the conveyance path of the belt-like material when the speed V1 of the transmitting conveyor 51 and the speed V2 of the receiving conveyor 52 becomes different from each other.
This method has an advantage that a change in the delivery speed of the belt-like material 1 can be handled with a simple structure. However, when the belt-like material 1 is a rubber member, it elongates by its own weight. Therefore, it is not preferred that this method be used to convey a rubber member which can be easily transformed, such as an unvulcanized rubber member for a tread extruded from an extrusion molding machine. Accordingly, the delivery of the belt-like material must be controlled by starting or stopping extrusion from the extrusion molding machine so that the belt-like material 1 should not elongate.
To cope with this problem, there is proposed a conveyor device 60 as shown in FIG. 5, which comprises a conveyor movable along a horizontal path and can convey a belt-like material 1 in such a state that the belt-like material 1 does not elongate and unrequired stress is not applied even when the extrusion speed from the extrusion molding machine is constant (for example, Japanese Patent Publication 2000-515473). The belt-like material 1 conveyed by an upper conveyor 61 which comprises a first conveyor belt 61b driven by drive means 61a and delivered at a predetermined rate V1 from an unshown feeder such as an extrusion molding machine is sent to a lower conveyor 63 which comprises a third conveyor belt 63b driven by drive means 63a through a central conveyor 62 which is a movable conveyor and supplied to a device such as a belt-like material processor. When the conveyance speed V2 of the lower conveyor 63 is lower than the conveyance speed V1 of the upper conveyor 61 and the belt-like material 1 is slacked by a reduction in tension shown by a broken line in FIG. 5, the above slack is detected by an optical sensor 64 installed near the front end 62F of the above central conveyor 62 and eliminated by adjusting the length of the belt-like material 1 by driving an unshown actuator incorporated in a servo unit 66 controlled by a controller 66 to move the above central conveyor 62 in a direction shown by an arrow B in FIG. 5. Even when the conveyance speed V2 of the lower conveyor 63 differs from the conveyance speed V1 of the upper conveyor 61, the belt-like material 1 can be thereby conveyed from an upper site to a lower site without being elongated.
However, in the above conventional conveyor device 60, the belt-like material 1 is simply descended to the lower conveyor 63 over the front end 62F of the central conveyor 62 to be carried on the lower conveyor 63. Thus, the belt-like material 1 can be conveyed from an upper site to a lower site in structure in the prior art. Therefore, the development of a conveyor device which can convey the belt-like material 1 from a lower site to an upper site without applying unrequired stress to the belt-like material 1 when the extruded tread is pulled up from a cooling water tank and conveyed to the molding step of laminating it with another member such as a cord, bead or belt is desired.
It is an object of the present invention which has been made in view of the above problem of the prior art to provide a conveyor device capable of conveying a belt-like material from a lower site to an upper site without elongating the belt-like material to be conveyed and applying unrequired stress thereto.
According to a first aspect of the present invention, there is provided a conveyor device comprising:
a first conveyor for conveying a belt-like material supplied from material supply means;
a second conveyor, comprising an inversion conveyor and a unit for expanding or contracting an expansion conveyor along a horizontal path above the first conveyor, for inverting the belt-like material received from the first conveyor and conveying it in an upward direction; and
an induction conveyor interposed between the first conveyor and the second conveyor and having at least one end movable in a vertical direction.
Since the belt-like material can be thereby conveyed in an upward direction while the length of the conveyance path is increased or reduced, it can be conveyed from a lower site to an upper site without being elongated and without applying unrequired stress thereto.
According to a second aspect of the present invention, there is provided a conveyor device which further comprises a third conveyor, comprising an induction conveyor having at least one end movable in a vertical direction and an inversion conveyor above the second conveyor, for inverting the belt-like material received from the second conveyor and conveying it in an upward direction. Thus, the belt-like material inverted by the second conveyor is returned to its first delivery state and conveyed in an upward direction.
According to a third aspect of the present invention, there is provided a conveyor device wherein the belt of the expansion conveyor is suspended by an upper intermediate roller and a lower intermediate roller interposed between main rollers, and only the main roller, the upper intermediate roller and the inversion roller are made movable to expand or contrast the expansion conveyor. Thereby, the belt-like material can be conveyed to the conveyor unit in the latter stage smoothly.
The above and other objects, features and advantages of the present invention will become apparent from the following description taken into connection with the following drawings.